Convicted killer Johnny Paul Penry, whose case helped spark national debate over whether mentally impaired inmates could be executed, had his death sentence overturned for the third time Wednesday. A divided Texas Court of Criminal Appeals sent the case back to trial for a new punishment phase in the 1979 slaying of an East Texas woman. The court ruling said jurors during his most recent retrial may not have properly considered his claims of mental impairment. Over more than a decade, the uneducated laborer became the face of mentally impaired killers across the country, winning two reversals from the U.S....